The wireless communications network has grown exponentially over the years. A Long-Term Evolution (LTE) system offers high peak data rates, low latency, improved system capacity, and low operating cost resulting from simplified network architecture. LTE systems, also known as the 4G system, also provide seamless integration to older wireless network, such as GSM, CDMA and Universal Mobile Telecommunication System (UMTS). In LTE systems, an evolved universal terrestrial radio access network (E-UTRAN) includes a plurality of evolved Node-Bs (eNodeBs or eNBs) communicating with a plurality of mobile stations, referred to as user equipments (UEs). The 3rd generation partner project (3GPP) network normally includes a hybrid of 2G/3G/4G systems. With the optimization of the network design, many improvements have developed over the evolution of various standards.
LTE networks are packet-switched (PS) IP networks. This means that the networks deliver all data traffic in IP packets, and provide users with Always-On IP Connectivity. When UE joins an LTE network, a Packet Data Network (PDN) address (i.e., the one that can be sued on the PDN) is assigned to the UE for its connection to the PDN. LTE calls the users “IP access connection” an evolved packet system (EPS) bearer, which is a connection between the UE and the PDN gateway (P-GW). The P-GW is the default gateway for the UEs IP access. LTE has defined a Default EPS Bearer to provide the Always-On IP Connectivity. By introducing Always-On IP Connectivity in 3GPP network, it became difficult for the subscriber to have explicit control of the traffic sent or received by its UE, which could lead to unexpected charging.
3GPP PS_Data_Off feature is thus introduced to meet the requirements. The PS_Data_Off feature prevents transport via 3GPP access of all IP packets except those related to 3GPP PS_Data_Off Exempt services. The UE discovers a P-GW supports 3GPP PS_Data_Off feature at initial attach and during the establishment of a PDN connection via the presence of the 3GPP PS_Data_Off Support Indication in the Create Session response message. When the UE requests a new PDN connectivity, the UE shall include the indication in the PCO within the PDN Connectivity Request message. When the UE changes its PS_Data_Off status, the UE shall report a change of its 3GPP PS_Data_Off status in PCO by using Bearer Resource Modification procedure. For IP Multimedia Subsystem (IMS) services, the UE shall inform the IMS domain in initial REGISTER request and subsequent re-REGISTER request.
As a result, the support of 3GPP PS_Data_Off feature introduce more issues and requirements that need to addressed.